According to Postman, what is the danger of TV as a "meta-medium"?

TV becomes the main source of cultivating knowledge in society-apex

The way TV is being corrupted by government and how the information is being threatened is what Postman was concern about, because many people don't have access to another source of information but TV and can be easily misinformed. No real knowledge is constructed on TV, because no standard and raw information is transmitted.